Title: Cervical Rib

Imaging Findings:
Figure Unilateral or bilateral rudimentary ribs arising from the seventh cervical vertebra (arrows).

Clinical:
Found in 0.5% of population and more common in females than males (1).
Majority are asymptomatic. However, compression of subclavian vessels or brachial plexus can produce a thoracic outlet syndrome in which hand pain is associated with elevation of the ipsilateral arm, or pulse intensity differences are detected at different arm positions.

Etiology:
Failure of embryologic fusion of cartilaginous costal anlage to vertebral body . Transverse processes average 4 cm in length (3). The seventh cervical vertebra transverse processes can be distinguished from those of the thoracic vertebra as the former are oriented caudally, from medial to lateral, on the anteroposterior view. Cervical ribs may fuse with adjacent first thoracic ribs to varying degrees (4), or possess pseudoarticulations (3).

References:
3. Steiner HA: Roentgenologic manifestations and clinical symptoms of rib abnormalities. Radiology 40: 175-178, Feb 1943.
4. Oestreich AE. Cervical rib simulating fracture of the first rib in suspected child abuse. Radiology 1996; 199: 582.
1. Fisher MS. Eve’s rib. Radiology 1981; 140:841.